This invention relates generally to detector circuit systems utilized for detecting foul line infractions during a game of bowling, and more particularly, to an improved foul line detector circuit employing an integrated circuit IC to activate a silicone controlled rectifier SCR which in turn selectively activates an indicator light and/or a buzzer device.
Foul line detectors are commonly employed in the game of bowling to detect, as by means of the interruption of a photoelectric light beam, the protrusion of a bowler's foot or leg across a foul line during the release of a bowler's toss. Foul line detectors have found application for timer circuits as well which are used to distinguish transient interruptions, such as ball passage, which should not result in a foul detection. One earlier disclosed detector system as described in U.S. Pat. No. 3,083,966, issued Apr. 2, 1963, to M. E. Untiedt, employed a photocell actuated by a suitable light source. The resistance thereof increases and current flow to a solenoid is dropped to deenergizing level. A shunting capacitor is used to maintain sufficient current to the solenoid for a given time delay to provide for noninterruption by transient conditions. Another foul detector is described in U.S. Pat. No. 3,170,689, issued Feb. 23, 1965, to Raymond E. Brown et al., wherein the foul detecting circuit is purely electronic solid state components and devices, to improve over previous detector circuits including mechanically-operating devices.
Another patented detector system is disclosed in U.S. Pat. No. 3,743,290, issued to Wlm. M. Crimmins et al. on July 3, 1973, wherein the control circuit included timer circuits with programmed unijunction transistors and electronic flip-flop circuits controlling SCR switching elements and triac switching elements.